In a mobile communication system, a radio communication environment around a base station changes when a buildings is constructed near the base station or installation conditions of its neighboring base stations change. Hence, it has been a common practice to perform a drive test where an operator uses a measurement vehicle carrying measurement equipment to measure states of signals received from a base station and collect measured data.
Although such measurement and collection is useful in optimizing coverage of the base station, for example, it has a problem of requiring a large number of man-hours and high cost. In view of this problem, 3GPP (3rd Generation Partnership Project) which is a standardization project of mobile communication systems is formulating a specification of MDT (Minimization of Drive Tests) for automating the measurement and collection by use of a user terminal held by a user (refer to Non-patent documents 1 and 2).